In a large pot or Dutch oven add andouille sausage. Cook over medium heat for 6-8 minutes, or until browned.
Remove sausage and drain on a paper towel-lined plate.
Measure remaining oil in the pot. Add enough oil to equal ¼ cup oil.
Add ½ cup flour. Reduce heat to medium-low and whisk roux for 30-40 minutes or until it is a chocolate brown color. Be careful not to let it burn.
Once roux is chocolate brown, add onion, bell pepper, celery, and garlic. Saute over medium-low heat for 7-8 minutes.
Add broth, making sure to scrape the bottom of the pot to loosen up any pieces that are stuck.
Add salt, pepper, thyme, cayenne, oregano, tomatoes, Worcestershire sauce, and bay leaf. Stir to combine.
Bring gumbo to a boil. Once ingredients are boiling, reduce heat to a simmer. Allow gumbo to simmer for 35-40 minutes, uncovered, or until it is reduced by almost half.
Add shrimp and sausage. Stir to combine. Continue simmering for 6-7 minutes or until shrimp are cooked through.
Remove bay leaf and serve shrimp and sausage gumbo over rice with fresh parsley.